This is Aerospace Medicine
Presented by the Aerospace Medical Association
1 of 71 Overview
Introduction Flight Environment Clinical Aerospace Medicine Operational Aerospace Medicine
2 of 71 Aerospace Medicine vs. Traditional Medicine
Medical Discipline Physiology Environment
Traditional Medicine Abnormal Normal
Aerospace Medicine Normal/Abnormal Abnormal
3 of 71 Brief History of Flight Medicine
• Advent of powered flight presented new physiologic demands such as altitude exposure • Aviation Medicine driven by WWI high losses of life due to physically unfit pilots • Development of manned space flight led to evolution of Aviation Medicine into Aerospace Medicine
4 of 71 Aerospace Medicine Practitioners
• Address needs of all who work, recreate, and travel in the air, sea, and space • Trained in medicine, with special knowledge of operating in extreme environments of flight, undersea, and space • Uniquely equipped to make decisions on selection and retention of aviators, divers, and space mission and space flight participants.
5 of 71 Aerospace Medicine Practitioners
Armed Forces across the globe Crew & Passenger Health Safety Policy Military Certification & Appeals Regulatory Compliance Airline Aeromedical Examiner Medical FAA/DOT training & oversight Evaluation & treatment : Departments Accident Investigation pathologic bubble Aerospace formation Medicine Physicians Osteo & soft tissue Astronaut selection & radionecrosis training Hyperbaric Space Wound Infections Medicine Agencies Clinical & basic science studies Thermal burns Space Development of Support to space agencies & Medical countermeasures Operations commercial space ventures Longitudinal Health
6 of 71 Aerospace Medicine Practitioners
• Aviation Medical • International Aviation Examiners (AMEs) Medical Examiners • Designated, trained, and • European Aviation Safety Agency supervised by the FAA Flight (EASA) Surgeons • Training provides an • Examine/certify civilian pilots understanding of aviation related • Training provides an problems, physiology, standards, understanding of aviation and administrative processes related problems, physiology, • 60 hr basic and 60 hr advanced standards, and administrative courses processes • One week course with mandatory refresher courses
7 of 71 Aerospace Medicine Practitioners
• Military Flight Surgeons • Caring for aviators and their families, manage aerospace medicine and public health programs • Special training programs: • Residency in Aerospace Medicine (RAM) • Non-RAM military courses
8 of 71 Aerospace Medicine Practitioners
• National Aeronautics and Space Administration (NASA) Flight Surgeon Duties • Medical care for astronaut corps and their families • Astronaut selection and mission training • Develops physiologic countermeasures for spaceflight • Ensures crew health and safety • Research promoting a better understanding of medical issues associated with spaceflight environment
9 of 71 Advanced Training in Aerospace Medicine
• United States • United Kingdom • Civilian Residencies Subspecialty of • University of Texas - Occupational Medicine Medical Branch • Wright State University • Civilian Fellowship: • Civilian Fellowships King’s College in • Mayo Clinic London • Military Residencies • Military Fellowship: • US Navy Royal Air Force (RAF) • US Army Centre of Aviation • US Air Force Medicine
10 of 71 Aerospace Medicine Practitioners (Non-Physicians)
• Aerospace Experimental • Flight Nurses Psychologists • Human Factors • Aerospace Physiologists Engineers • Bioenvironmental • Industrial Hygienists Engineers • Radiation Health • Cognitive Psychologists Professionals • Environmental Health • Systems Engineers Professionals
11 of 71 Advanced Training in Aerospace Medicine
• Other countries also have advanced training in aerospace medicine with military and civilian components
12 of 71 The Flight Environment
13 of 71 Theory of Flight
• Atmospheric flight • Space Flight Bernoulli and Newton Suborbital and Orbital described the concept Lunar and of lift, when air flows Interplanetary over a wing.
14 of 71 The Atmosphere
Composition
Gases Additional • Nitrogen 78 % Components (at SL 592.8 mmHg) Solid particles • Oxygen 21% (at SL 159.6 mmHg) • Dust • Other 1% • Sea Salt (at SL 76 mmHg)
15 of 71 The Atmosphere
• Gaseous mass surrounding Earth which is retained by the Earth’s gravitational field • Governed by gas laws
16 of 71 Key Atmospheric Properties in Ascent • Temperature • Oxygen • Pressure • Radiation • Humidity
17 of 71 The Atmosphere
Pressure: Pressure: Units of Measurement Reference Measurements • International Civil At sea level, (59°F or 15°C) Aviation Organization atmospheric pressure is: (ICAO) standard = 760 mmHg atmosphere = 29.92 inches Hg • International = 1013.2 millibars Atmosphere At 18,000 ft (5454.5m) • US Standard atmospheric pressure is Atmosphere 380 mmHg
18 of 71 Atmospheric Pressure & Altitude
1 atmosphere pressure = 760 mmHg = sea level ¾ atmospheric pressure = 570 mmHg = 8,000 ft (2424 m) ½ atmospheric pressure = 380 mmHg = 18,000 ft (5454.5 m) ¼ atmospheric pressure = 190 mmHg = 33,500 ft (10,151.5 m)
19 of 71 Atmosphere
Biosphere Characteristic Highlights Troposphere • Site of the majority of aviation activity • Temperature Lapse Rate • Temperature Decreases until Tropopause (30,000 ft or 9144 m) at poles & 60,000 ft (18,288 m ) at equator
Stratosphere • Contains Ozone layer, important for UV radiation protection
Mesosphere • Coldest sphere • -110 ˚C at 290,000 ft (85 km) Thermosphere • Charged particles modified by solar flare Exosphere • Sparse particle collisions • Hydrogen & Helium • Edge of Space
20 of 71 Aerospace Physiology
Respiration Acceleration Cardiovascular System Gravitational Effects Spatial Orientation Vibration Bioacoustics Hypobaria Vision Hyperbaria Sleep and Circadian Other Physical Factors Rhythms Human Factors
21 of 71 Respiration: Gas Laws
• Pressure changes at different altitudes creates various physiologic stresses i.e., hypoxia, decompression • These changes are governed by the Gas Laws such as Boyle’s Law, Dalton’s Law, Henry’s Law • Example: Body cavity volume expansion (GI tract, middle ear, and teeth) with altitude is governed by Boyle’s Law
22 of 71 Respiration
External Respiration Internal Respiration (Ventilation) Chemical reaction at Exchange of gases the cellular level of between body and carbohydrates and atmosphere oxygen, producing energy as well as carbon dioxide
23 of 71 Respiration: Gas Exchange
• Oxygen: • Transported in the body via hemoglobin in the red blood cells and very little in physical solution • Carbon dioxide: • Transport of the waste gas mainly in solution in the blood and 5% via hemoglobin • Gas exchange: • Occurs at the alveolocapillary membrane (oxygen diffuses from alveolus to capillary and combines with hemoglobin,
CO2 diffuses from blood into alveolus and is exhaled)
24 of 71 Respiration
Hypoxic Hypoxia Hypemic Hypoxia Oxygen deficiency from ineffective Oxygen deficiency from reduced gas exchange at lung or oxygen carrying capacity in the inadequate oxygen inspiration blood
Causes of Hypoxia
Histotoxic Hypoxia Stagnant Hypoxia Oxygen deficiency from inability to use oxygen at the molecular level Oxygen deficiency from inadequate delivery of blood flow.
25 of 71 Hypobaria
Altitude Effective (feet/meters) Performance Time Increased High Low Low Partial Danger of Altitude Pressure Pressure O 18,000/6,000 20-30 min 2 Hypoxia
25,000/8,333 3-5 min
Insidious onset makes hypoxia a real danger in high 35,000/11,666 1 min – 30 altitude flight. secs 50,000/16,666 9-12 secs
26 of 71 Hypobaria: Decompression Sickness Altitude Decompression Ascent Sickness (DCS)
Decompression Barometric Pressure • Subset of Decompression (PB) Illness (DCI) Decrease • DCI includes: • Arterial Gas Supersaturation Embolism (AGE) • Ebullism PN2 > PB • Trapped gas • Result of decompression in Pathologic (Nitrogen) accordance with Henry’s Bubble Formation Gas Law .
DCS Not all bubble formation with decompression leads to DCS.
27 of 71 Hypobaria: Symptoms of Altitude DCS
• Limb pain: at least 70% of all • Neurologic: about 1-8% of all symptoms symptoms • Most common presentation • Cold sweat, dizziness, edema, inappropriate or sudden onset of • Typically joint or muscle fatigue, headache, light pain headedness, loss of consciousness, motor and/or sensory loss, nausea, tremor • Skin symptoms: about (shakes), vertigo 13% of all symptoms • Pulmonary: about 3% of all • Mottling, pins & needles, symptoms tingling, prickling • Cough, dyspnea (difficult or labored breathing), substernal distress (tightness and/or pain in chest, especially during inspiration); sometimes called Chokes
28 of 71 Altitude Hypobaria: Treatment of DCS
• Immediate treatment in the aircraft – 100% oxygen (until told to stop by qualified physician) – Descend as soon as practical – Declare In-Flight Emergency (IFE) – Land at the nearest airfield with qualified medical assistance available Symptoms may resolve during descent ! • After landing – Hyperbaric Oxygen Therapy (HBOT): compresses bubbles, increasing circulation, and provides more O2 to tissues – Specialty care for serious DCS symptoms (respiratory or neurologic) or those which do not resolve during descent/repressurization; possible neurologic consult
29 of 71 Hypobaria: Protection from DCS
• Adequately pressurized cabin • Denitrogenation by preoxygenation • Pre-Breathing 100% oxygen to “off-gas” nitrogen • Before decompression • Same value, if done below 16,000 ft
30 of 71 Acceleration, Inertial Forces & Cardiovascular System
CO = MAP/ TPR -Gz Represents the ability of the system to provide adequate blood flow • Accelerative stress challenges the CV system’s ability to maintain blood flow to all vital +Gx +Gy organs, especially the brain -G y -G • Accelerative forces may also x impede venous blood return to the heart • Goal: Adequate End Organ Perfusion +Gz
31 of 71 Acceleration Effects
High Performance Aircraft • G-induced Loss Of Consciousness (G-LOC): state of unconsciousness when the G-forces reduce blood flow to the brain below the critical level
• Push Pull Effect: Decreased +Gz tolerance resulting from preceding relative -Gz
32 of 71 Acceleration
Human Tolerance to +Gz Long duration ( >1 sec) Short duration (<1 sec)
• + 2 Gz • Compression into seat • Movement Difficult • + 3 G • Up to +40 Gz depending on body z position • Extreme heaviness of limbs and body • Impossible to move or escape from aircraft
• Greater than +3 Gz • “Dimming” or “ graying” of vision, and possible G-LOC
33 of 71 Space Flight Effects
• Microgravity affects blood and interstitial fluid flow (approximately 1-2 liters shift towards the head and torso) • Bone demineralization leads to increased loss of calcium in urine and increased risk of kidney stones • Muscle mass reduction • Space motion sickness • Radiation exposure • Decreased immune system function • Psychology/Human factors
34 of 71 Spatial Orientation
• Visual (most important), vestibular, somatosensory (seat-of the-pants), and auditory systems
• Easily confused when moving in 3 planes of motion (pitch, yaw, and roll)
• Disorientation is a leading contributor to many fatal aircraft accidents
35 of 71 Vision
• Vision is a key factor for spatial orientation in flight • Errors may occur in visual perception • Color vision deficiencies can affect up to 8% of men and 2% of women.
Identifying these deficiencies is becoming more important as aircraft and air traffic control displays utilize colors and visual cues to display critical information.
36 of 71 Bioacoustics
Noise in aviation can be detrimental to hearing & communication
dBA Sound 20 Whisper at 5 ft. 50-70 Normal Conversation 100-110 Power Lawn Mower 130 Pain Threshold for Humans 140-160 Jet Engine 167 Saturn V Rocket
37 of 71 Vibration
• Vibration is oscillatory motion in dynamic systems • Human body most sensitive to vibration in vertical direction • Vibration affects a variety of body systems • General discomfort at 4.5-9 cycles per second (cps) • Abdominal pain at 4.5-10 cps • Lumbosacral pain at 8-12 cps • Head sensations at 13-20 cps
38 of 71 Other Physical Factors Associated with Flying
• Thermal • Extreme temperature swings in aviation (e.g. hot in cockpit on tarmac & freezing cold at altitude) • Radiation • Air travel at high altitudes • Risk for commercial aviation and spaceflight crews • Toxicology • Importance of knowledge of toxins in aviation (jet fuels, release of toxic fumes in fires, alcohol in blood versus vitreous, etc.)
39 of 71 Human Factors
• By definition, Human Factors is the impact of human behavior, abilities, limitations, and other characteristics to the design of tools, machines, systems, tasks, jobs, and environments for productive, safe, comfortable, and effective human use. • The goal of Human Factors is to apply knowledge in designing systems that work, accommodating the limits of human performance.
40 of 71 Human Factors
• Human-Machine Interface • Human Error implicated in 60-80% of accidents in complex, high technology systems • Task and information overload is critical issue • Science of color, size, position of switches/knobs, etc. and relevance to mission drive design
41 of 71 Human Factors
Sleep & Circadian Rhythms
• Internal body clock shifts with travel and work schedule and may impairs performance • Need to plan crew work-rest cycles to avoid accidents
42 of 71 Life Support Systems
Oxygen Systems
• Dilutor Demand • Pressure Demand with • Flow of oxygen proportional Regulator to cabin altitude [100% • Mounted on panel, seat or mask oxygen at 33,000 ft (10,058 m)] • Regulator attached to mask directly or via hose • Pressure Demand • Continuous Flow • Oxygen supplied with slight overpressure > 10,000 ft to • Passenger system, exhaled air full pressure breathing collected in bag to economize oxygen use • > 38,000 ft (11,582 m) • May be chemically generated • UK: >40,000 ft (12,192 m) for short term emergency use
43 of 71 Cabin Air Quality
Temperature Ozone
Carbon Dioxide Humidity
Oxygen Bioaerosols
Cabin Air Pressure Quality Tobacco Factors
44 of 71 Cabin Air Quality
Relative Humidity Air Recirculation • At altitude in cabin ~ 6-10%, • Complete air exchange every flight deck ~ 3% 3-4 min (homes q 12 min) • Due to very dry ambient air at • Up to 30-50% altitude • High efficiency particulate air • Air conditioned air filter filtration (efficient to 0.3 entering AC cabin has micrometers) relative humidity < 1% Carbon Dioxide • Irritation of eyes / sense of • 0.5 % by volume (sea level dry mucous membranes equivalent) • Plasma osmolality maintained by homeostatic renal function
45 of 71 Life Support Systems
Airline Medical Systems
• Minimize risks to passengers • Cockpit emergency oxygen is via • Avoid unscheduled diversions a compressed oxygen system and • Onboard emergency medical is separate from passenger capabilities are limited (airline emergency oxygen medical kits) • Emergency oxygen: 10-20 minute • Communication with ground supply for passengers produced support from internal airline with chemical oxygen generators medical staff or contracted staff • Limited number of walk- • Passengers requiring medical around bottles for crew oxygen must make separate arrangements with the airline
46 of 71 Clinical Aerospace Medicine
47 of 71 Fitness for Duty & Return to Flight Status
• Screen aviators, astronauts, air traffic control personnel for risk of sudden incapacitation or degradation in skills • Applies to all areas of medicine • Applies to all types of aviators, i.e. military, commercial pilots, private pilots, and flight crew
48 of 71 Fitness for Duty & Return to Flight Status
Medical Standards • Civilian standards (i.e. FAA, NASA, EASA) and military standards (Air Force, Navy, Army) may differ due to different aircraft, mission requirements, and operating environments. Examples include: • Type of aircraft - Multi-crew Aircraft vs. Single Seat Fighter Jet • Type of Operation/Environment • Recreational vs. Airline Transport Operations • Wartime, Remote environments • Initial selection vs. Maintenance of Standard
49 of 71 Fitness for Duty & Return to Flight Status: Multisystem Approach
Cardiology Pulmonology Ophthalmology Otolaryngology Psychiatry and Psychology Neurology Other Conditions
50 of 71 Fitness for Duty & Return to Flight Status
Cardiology Assessment important to mitigate risk of sudden/ subtle incapacitation in aviation and space travel
• Arrhythmias • Coronary disease • Valvular disease • Syncope • Pacemakers
51 of 71 Fitness for Duty & Return to Flight Status
Pulmonology • Trapped gas (like bullae, for example) increase risk of barotrauma with changes in pressure • Lung disease leading to hypoxia under hypobaric conditions may increase need for oxygen in flight and impact safety • Sleep apnea and resulting fatigue can impact aviation safety
52 of 71 Fitness for Duty & Return to Flight Status
Ophthalmology Importance of Vision in Aviation
• Distant, Intermediate & • Depth perception and Near Vision stereopsis • Target acquisition (less • Terrain avoidance important with modern • Landing weapons) • Maintenance of visual • Ability to safely acuity operate the aircraft • Refractive surgery • See and be seen in • Refractive correction visual flight rules with glasses /contact (VFR) lenses • Color Vision • Instrument displays
53 of 71 Fitness for Duty & Return to Flight Status
Otolaryngology: Key Issues • Hearing and hearing protection • Vestibular system • Barotrauma due to trapped gas in sinus and ear cavities
54 of 71 Fitness for Duty & Return to Flight Status
Psychology & Psychiatry The absence of Psychological and psychiatric factors important with long significant psychiatric term isolation and in small disease, including groups (multi-crew aircraft) psychosis and • Long-duration spaceflight personality disorders, • Exploration, Orbital is an important • Commercial aircraft - locked cockpit door prerequisite to safe • Commercial operation of Spaceflight/Spaceflight aerospace systems participants
55 of 71 Fitness for Duty & Return to Flight Status
Neurology Seizures Neurological evaluations for TIA & Stroke flight fitness optimize safety Traumatic Brain Injury and performance by Unexplained Loss of focusing upon conditions Consciousness with the potential to lead to Intracranial Masses & sudden/subtle Cancers incapacitation HIV & AIDS Sleep Disorders Disqualifying Medications
56 of 71 Fitness for Duty & Return to Flight Status
Other Medical & Surgical Conditions Evaluation of any condition or treatment that may Aerospace Practitioners potentially: Continuously Review • Impact flight safety Changing Medical • Influence crew Practices, Procedures, performance in flight and Medications for Use • Influence behavior or cognitive processing in the Flight & Space • Lead to sudden/subtle Environments incapacitation
57 of 71 Fitness for Duty & Return to Flight Status
Health Maintenance of Aircrew Well-being: Interaction between physical, psychological and emotional factors • Importance of regular crew rest cycles • Importance of exercise and diet • Importance of avoidance of self induced stressors, i.e., alcohol, nicotine, caffeine • Importance of maintaining balance on life • Work/family life
58 of 71 Fitness for Duty & Return to Flight Status
Longitudinal Health & Wellness Surveillance • Ensure aircrew have long, safe, and productive careers • Measure and evaluate emerging occupational risks/exposures or environmental threats
59 of 71 Clinical Hyperbaric Medicine
• Hyperbaric Oxygen Therapy Indications for HBOT (HBOT) addresses pathologic Decompression Sickness bubble formation most frequently Air Gas Embolism encountered in flying diving and CO/CN Poisoning space operations activities, selected Compromised Flaps & Grafts infections, wounds and traumatic Crush Injury injuries. Exceptional Blood Loss Anemia • Recent investigations have provided Thermal Burns a better understanding of basic Intracranial Abscess science mechanisms underlying Necrotizing Soft Tissue Infection Undersea & Hyperbaric Medicine Refractory Osteomyelitis Society approved clinical indications Delayed Radiation Injury (Osteoradionecrosis & Soft Tissue Radionecrosis) • Training options : Comprehensive Central Retinal Artery Occlusion Hyperbaric Medicine Fellowship (1 yr.) , board certification and courses
60 of 71 Operational Aerospace Medicine
61 of 71 Operational Aerospace Medicine
• Address challenges of operating aerospace vehicles in a physiologically challenging environment • Conducted in military and civilian setting • Management and prevention of medical events during operations
62 of 71 Operational Aerospace Medicine
• Issues in civilian operations • Commercial air transport flight operations • Deep vein thrombosis prophylaxis in susceptible individuals, • Circadian rhythm issues • Potential for spread of infectious diseases • Consideration of radiation exposure • Commercial spaceflight operations
63 of 71 Operational Aerospace Medicine
• Military crew members can be required to operate at very high altitudes for the purposes of reconnaissance, combat, or routine training operations
• The unique stresses of extreme altitude operations require special protective equipment and training
Photographs courtesy of the Federal Aviation Administration 64 of 71 Operational Aerospace Medicine
• Aeromedical Transportation encompasses the transport and inflight care of patients of different acuity levels.
• Noise, vibration, communication, pressure changes and combat activities can impact ability to deliver care in these settings.
• These transports include fixed-wing aircraft and rotary wing aircraft.
Photographs courtesy of the Federal Aviation Administration 65 of 71 Operational Aerospace Medicine
• Hyperbaric Medicine Practitioners support a variety of occupational, training, and remote diving activities
• Oil Industry • Astronaut Dive Training for Extravehicular Activities • Underwater Search & Rescue Support
Photograph courtesy of the Federal Aviation Administration 66 of 71 Survival, Search & Rescue
• Crash Worthiness – Primary/Secondary Protection • The aircraft and its systems are a life support system and its thoughtful design may greatly aid in the survivability of a crash • Search & Rescue Systems • Beacons • Increased use of satellite technology • Organized systems in civilian environment and military • Importance of survival training
Photograph courtesy of the Federal Aviation Administration 67 of 71 Accident Investigation
• Significant improvements in accident rate and data since the 1960s due to: • Improved operational procedures • Technological developments • Application of lessons learned from accident investigations
Photograph courtesy of the Federal Aviation Administration 68 of 71 Accident Investigation
Civilians and Military Methodical & use similar resources multidisciplinary • Flight Surgeons • Emergency Response Teams evaluation of • Hazardous Materials Specialists • Aviation Experts aspects that may • Airframe Maintenance & Engineering Experts have contributed to • Air Traffic & Air Field Experts • Pathologists & Toxicologists an accident • Dentists • Coroners • Law Enforcement Officers
69 of 71 Accident Investigation
• Accident Summary • On Scene Investigation • Nature of Accident • Fire, Blast, Acceleration Evidence • Communication with ATC • Grid Debris and Victims • Flight Data Recorder • Mechanism of Injury • Witness Reports • Photography • Weather Conditions • X-Rays • Pilot Information • Toxicology • Certification & Class • Body Fluids & Tissues of Key Crew Evaluated • Age & Health History • Forensics • Historical Flight Performance • Forensic Dentistry • Assigned AME • DNA • Aircraft Certification • Corroboration with Archival Accident • Type of Aircraft Data • Vehicle Maintenance Information
70 of 71 Acknowledgements
• Anthony Artino PhD • David Rhodes MD MPH • Professor Michael • Philip Scarpa MD Bagshaw • Erich Schroeder MD MPH • Eilis Boudreau MD PhD • Greg Shaskan MD • Yvette DeBois MD MPH • Jan Stepanek MD MPH • Marvin Jackson MD • Jeffrey Sventek MS • Jeff Myers MD • James Webb PhD
71 of 71